FIELD OF THE INVENTION
This invention relates to gaskets which seal against liquids. Polar liquids such as mixtures containing water or coolant are frequently encountered in engines. This particular type of gasketing is found in engines. Although the gasketing can seal against all fluids, it is a characteristic of this gasketing that it seals polar liquids particularly well.
The gasketing described herein, therefore, seals particularly well against liquids and liquid mixtures which contain water and/or coolant. Although the gasketing can also seal against non-polar liquids, it forms a better seal against polar liquids than it seals other fluids.
Excellent facing material is provided for cylinder head gaskets which must seal against coolant/water mixtures. The ability to seal against the coolant/water liquids is one of the most desired properties in cylinder head facing sheets.
Engine gasket facings have been prepared from mixtures of fibers, fillers and binders. This type of gasketing material relies on soft binders to achieve a sufficient sealing ability in the gasket sheet. Binders allow a compression of the sheet and obtain a sealing of internal pores. Traditionally, gasketing materials require binder levels which seal out the polar liquids. But, the higher binder levels are more costly, and also result in lower torque retention, an increased creep relaxation, and have a lower temperature stability.
The invention described herein provides gasketing materials which have lower binder levels without a drop in sealability against polar liquids. Specializing in sealing polar liquids, the gasketing described herein gives levels of polar liquid sealability which range from good to very excellent.
The present gasketing sheet materials can lower binder levels to 0% by weight binder. Excellent torque retention and creep resistance are obtained with the lower binder levels. Good to excellent sealability (sealing ability) against or in the presence of polar liquids is obtained even at 0% binder levels.